RE: setting up a mail server.

From: "Robert Boucneau" <rboucneau tuckernt net>

To: <fedora-list redhat com>

Subject: RE: setting up a mail server.

Date: Thu, 8 Apr 2004 12:02:16 -0600

Hi Paul,
You've been given some pretty good suggestions -- get fetchmail set up and
it will drag you messages down from the ISP to the local computer. The
explanations seemed a bit on the short side, so I'm expanding...
You'll have set up five "accounts" (one for each mail recipient.)
Fetchmail sits on your local machine and every once and a while (3 minutes?,
5? ...you configure) it will log onto the ISP's mail server, get the for
each user mail, and deliver it to (something like) /var/spool/mail/(account
name).
When it delivers the mail, it will actually use "procmail" as the Local
Delivery Agent (LDA) -- this means it will hand the mail over to the
procmail program to put into the /var/spool/mail/(account name) file. The
"beauty" of this is that while procmail is holding the mail on the way to
the inbox, we can look at it and make some changes...this is where you'd
scan for viruses and spam, for instance...or lots of other things (see
http://pm-doc.sourceforge.net/pm-tips.html for some more stuff on what
procmail can do...)
To scan for viruses and for spam, you'll need two packages (spamassassin and
clamav) -- I'm sure there are many other options, but it seems these two are
the general favorites. Get those installed (and make sure you have the most
up-to-date versions by going to their home pages and checking.) Set up
spamassassin's "spamd" daemon to run in the background (see the man page,
but basically you just need to tell Fedora to run the "spamassassin" daemon
during startup.)
Then go to the user's home on you "mail server." This is probably in
/home/(account name). Make a mail directory (mkdir mail). Back in the home
directory (/home/(account name) ) edit a file called ".procmailrc" . This
file will be blank, but can have instructions that tell procmail what to do
with your mail while it is getting ready to deliver it.
The tips page I referenced above will give you more info, but the part that
is important for your purposes will need to look something like this: (watch
out that procmail.log doesn't grow too big, because it can...)
#---------BEGIN-------------
MAILDIR=/home/(account name)/mail
LOGABSTRACT=yes
LOGFILE=/home/(account name)/procmail.log
# If this is not a "big" message (bigger than 256K), then...
# Lets run it through spamassassin for a quick idea of content
# We use spamc to client <-> server it through the spamd
# spamassassin daemon
:0 fw
* !> 256000
| /usr/bin/spamc
# This says, "Here's a recipe (:0), it's a filter (f), wait for it to
complete (w)
# Check (*) and see how big the message is. If it is not (!) bigger (>)
than 256000 bytes
# run it through (|) spamc
# If it is spam, then chuck it onto the floor
:0
* ^X-Spam-Level: \*\*\*\*\*\*\*
{ HOST = this.is.deleted }
# This says, "Here's a recipe (:0) (and, since that's all it says, it means
that this could be a
# final delivery option for the message...) Check (*) if there is a header
(by default) that
# was added by SpamAssassin that indicates spam (^, means "line begins
with") (5 stars means
# "Most likely spam", for this recipe we check for 7 or more -- ) then
change the "HOST" (the
# name of the system that will handle the message) to "this.is.deleted" --
which very quickly
# just makes the message disappear...
:0c:
* ^X-Spam-Status: Yes
passedspam
# This says, "Here's a recipe (:0), please use a copy of the message (C),
and lock the destination
# file is we deliver (:). If (*) the messages has a header that says
SpamAssassin think this is SPAM
# then drop the copy into the passedspam file (this, combined with the
previous message throws away
# obvious spam (more than 7 *'s) while saving a copy of 5-star or 6-star
spam so the administrator can
# continue to educate himself and train SpamAssassin by looking at the
contents of passedspam.
# Okay...not spam (or not *bad* spam), so lets check for virii
:0 HB :
* !? clamscan --mbox -r --quiet -
viruses
# This says, "Here's a recipe (:0), please work on both the headers (H) and
the body (B), please
# lock the destination file (:) if we deliver. If (*), not (!) a return
value from calling (?)
# clamscan on a mbox style file, recursively (-r), and without lots of text
output (--quiet) on
# a data stream (-), then there is a virus in the file -- deliver it to the
viruses file (and
# not to the recipient...
# And then, assuming we haven't thrown it away as spam, filed it as a virus,
or otherwise gotten rid
# of it, we're done with instructions -- procmail can go ahead and deliver
the message....
#----------END--------------
I hope this helps...
Bob
-----Original Message-----
From: fedora-list-bounces redhat com
[mailto:fedora-list-bounces redhat com]On Behalf Of paul
Sent: Wednesday, April 07, 2004 5:06 PM
To: For users of Fedora Core releases
Subject: setting up a mail server.
Hi
I'm a newbie and need some help in setting up a mail server for my
local network. i have 5 machines on local network all linked together by
a hardwire router and connected to the Internet by cable modem
(telewest). i would like to download all messages to one machine scan
for virus and spam then forward to others on my network, the messages
are currently stored by telewest in 5 pop3 mailboxes.
can someone please help or point me in the right direction. i've tried
googling but got confused.
p.s. 3 of the machines are windows the others are linux fedora.
Registered Linux user #349975
Cheap Inkjet Cartridges www.webstersinks.co.uk
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